CN104192994A - Membrane bioreactor - Google Patents

Abstract

The invention discloses a membrane bioreactor which comprises a membrane assembly and a gas-water separation device, wherein the membrane assembly can be arranged in a mud-water mixed solution; the membrane assembly comprises a filter membrane and a water production inner cavity which is formed by the filter membrane; the water production inner cavity is communicated with the gas-water separation device through a water production pipe; the gas-liquid separation device comprises a piston barrel and a piston which is arranged in the piston barrel and used for dividing the inner cavity of the piston barrel into a front cavity and a rear cavity; a check valve which is capable of communicating from the front cavity to the rear cavity is arranged on the piston; the water production pipe is communicated with the front cavity of the piston barrel; and a water outlet pipe which is externally connected with a water production pump and a gas supply pipe which is externally connected with a gas source are communicated with the rear cavity of the piston barrel. According to the membrane bioreactor, the gas-water separation device is arranged and the gas source is used as a power source of the backwashing, so that large-scale equipment such as a backwashing water pump is not used and thus the engineering cost and the water charge per ton are reduced. Practices prove that the rise of pressure is faster than that of the backwashing water pump, so that the membrane surface can be more effectively cleaned, the processing effect is good and the unit energy consumption is low.

Description

A membrane bioreactor

technical field

The invention is used in the technical field of water purification treatment, and in particular relates to a membrane bioreactor.

Background technique

Membrane bioreactor (Membrane Bioreactor-MBR) is an emerging water treatment technology, which is an organic combination of traditional sewage biological treatment process and membrane separation technology, and has been widely used in sewage treatment. The principle of membrane bioreactor is to use membrane separation technology to replace the secondary sedimentation tank in the traditional activated sludge method. Membrane bioreactors are generally composed of two parts: a membrane module and a bioreactor. According to the position of the membrane module, it can be divided into two types: separate type and integrated type. Among them, the integrated type is to install the membrane module and the bioreactor separately. The mixed solution of the bioreactor enters the membrane module after being pressurized by the pump. Under the action of pressure, the liquid in the mixed solution permeates the membrane and becomes the treated effluent of the system. Activated sludge and particulate matter are trapped in the bioreactor by the membrane module, thereby retaining a higher concentration of activated sludge. Due to the many advantages of the membrane bioreactor, it has been widely used at home and abroad.

However, since the membrane surface of the integrated membrane bioreactor is in direct contact with the high-concentration activated sludge in the reactor, it is very easy to produce concentration polarization, resulting in pollution of the membrane surface; Backwashing is a process in which the product water is used as flushing water and flows out from the filter membrane on the product water side to the water inlet side under pressure. However, the entire water backwashing process consumes a lot of energy, resulting in a high cost per ton of water treatment for membrane bioreactors, which restricts the development of membrane bioreactor technology. It is imminent to adopt a backwash method that can overcome the defect of high energy consumption of traditional membrane bioreactor technology.

Contents of the invention

In order to solve the above problems, the present invention provides a membrane bioreactor with good treatment effect and low unit energy consumption.

The technical solution adopted by the present invention to solve the technical problem is: a membrane bioreactor, including a membrane module and a gas-water separation device that can be placed in the mud-water mixture, the membrane module includes a filter membrane and is formed by the filter membrane. The inner cavity of water production, the inner cavity of water production communicates with the gas-water separation device through the water production pipe, the gas-water separation device includes a piston cylinder and is arranged in the piston cylinder and separates the inner cavity of the piston cylinder It is the piston of the front cavity and the rear cavity. The piston is provided with a one-way valve that can lead the direction from the front cavity to the rear cavity. The water production pipe communicates with the front cavity of the piston cylinder and communicates with the rear cavity of the piston cylinder. It is equipped with an outlet pipeline connected to an external produced water pump and an air supply pipeline connected to an external gas source.

As a further improvement of the technical solution of the present invention, there is at least one membrane module, and when there are multiple membrane modules, each membrane module is arranged in parallel, and the water production pipe includes a water production branch pipe communicating with the water production inner cavity of each membrane module And each of the produced water branch pipes is connected to the produced water main pipe of the gas-water separation device.

As a further improvement of the technical solution of the present invention, a first shut-off valve and a second shut-off valve are provided along the water outlet pipeline, and the air supply pipeline merges into the water outlet pipeline between the first shut-off valve and the second shut-off valve. , the air supply pipeline is provided with a third shut-off valve.

As a further improvement of the technical solution of the present invention, an aeration pipeline is further included, and the aeration pipeline forms several aeration ports under the membrane module.

As a further improvement of the technical solution of the present invention, the aeration pipeline is in communication with the gas source and connected in parallel with the air supply pipeline, and a fourth cut-off valve is provided on the aeration pipeline.

As a further improvement of the technical solution of the present invention, the air source is an air compressor.

As a further improvement of the technical solution of the present invention, it also includes a main control box communicating with the first shut-off valve, the second shut-off valve, the third shut-off valve, the fourth shut-off valve, the produced water pump and the air compressor.

As a further improvement of the technical solution of the present invention, the water outlet of the produced water pump is externally connected to a water collection device or an advanced treatment device.

As a further improvement of the technical solution of the present invention, the one-way valve is one or more one-way doors arranged on the piston that can be opened to the rear chamber.

As a further improvement of the technical solution of the present invention, the filter membrane is an ultrafiltration membrane.

Beneficial effects of the present invention:

The working principle of this membrane bioreactor is as follows: the produced water enters the produced water inner chamber through the filter membrane from the outside of each membrane module, and collects in the produced water main pipe through the produced water branch pipe; the piston in the gas-water separation device is set to the top, and the one-way valve is open state, the produced water flows into the outlet pipe, enters the produced water pump by controlling the first stop valve and the second stop valve; at the same time, the air blown by the air compressor enters the aeration pipeline through the fourth stop valve, and passes through The air port enters the membrane separation area to flush and clean the membrane components. When the filter membrane of the membrane module needs to be cleaned, turn off the produced water pump, put the second shut-off valve in the closed state, close the fourth shut-off valve at the same time, open the third shut-off valve, and the air from the air compressor enters the gas-water separation through the outlet pipe. device, the one-way valve in the gas-water separation device is closed, the piston moves down under the pressure, and the produced water is forced to flow out of the membrane module along the radial direction and reverse direction of the filter membrane, and at the same time, the fouling is discharged to play a role of backwash cleaning .

Compared with the prior art, the present invention has the following beneficial effects:

(1) The present invention adopts a perfect pipeline design and uses an aeration gas source to replace the backwash water pump, which saves expensive large-scale equipment such as backwash water pumps, thereby reducing engineering costs and ton water costs.

(2) The present invention adopts an air-water separation device and uses an air source as the power source for backwashing. Practice has proved that the pressure rises faster than the backwashing water pump, and can clean the membrane surface more effectively. The treatment effect is good and the unit energy consumption is low. .

(3) Generally, when the pressure of the gas source is higher than the bubble point of the produced water, the mixture of the produced water will boil and the backwash cannot be carried out. The product water in the product water pipe can achieve efficient backwashing without additional control of the pressure of the air source.

(4) Compared with the backwash pump, the operation is faster. All components are automatically controlled and connected to the main control box, which can realize frequent and fast backwashing in a short period at a lower level of energy consumption.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing:

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

Detailed ways

With reference to Fig. 1, the present invention provides a kind of membrane bioreactor, comprises the membrane assembly 1 that can be placed in the mud-water mixture and gas-water separation device 2, and described membrane assembly 1 comprises ultrafiltration membrane and is formed by described filtration membrane A water-producing inner chamber, the water-producing inner chamber is communicated with the gas-water separation device 2 through a water-producing pipe, and the gas-water separation device 2 includes a piston cylinder 21 and is arranged in the piston cylinder 21 and the piston cylinder 21. The inner cavity is divided into a front cavity 22 and a piston 24 of a rear cavity 23. The piston 24 is provided with a one-way valve 25 that can connect the front cavity 22 to the rear cavity 23. The cavity 22 communicates with the rear cavity 23 of the piston barrel 21 and is provided with the water outlet pipeline 3 of the external water production pump and the air supply pipeline 4 of the external air compressor. The water outlet of the produced water pump is externally connected to a water collection device or an advanced treatment device.

Wherein, there is at least one membrane module 1, and when there are multiple membrane modules 1, each membrane module 1 is arranged in parallel, and the water production pipe includes a water production branch pipe 11 communicated with the water production inner chamber of each membrane module 1 and a Each of the produced water branch pipes 11 merges into the produced water main pipe 12 of the gas-water separation device 2 .

The one-way valve 25 is one or more one-way doors arranged on the piston 24 that can be opened to the rear cavity 23 .

A first shut-off valve 51 and a second shut-off valve 52 are provided along the outlet pipeline 3, and the air supply pipeline 4 flows into the outlet pipeline 3 between the first shut-off valve 51 and the second shut-off valve 52, so that The air supply pipeline 4 is provided with a third stop valve 53 .

It also includes an aeration pipeline 6 which forms a number of aeration ports 61 under the membrane module 1 . The aeration pipeline 6 communicates with the air source and is connected in parallel with the air supply pipeline 4 , and the aeration pipeline 6 is provided with a fourth cut-off valve 54 .

The first shut-off valve 51 , the second shut-off valve 52 , the third shut-off valve 53 , the fourth shut-off valve 54 , the produced water pump and the air compressor are all in communication with the main control box.

The working principle of this membrane bioreactor is: the water produced enters the inner chamber of the water produced through the filter membrane from the outside of each membrane module 1, and is collected in the water produced main pipe 12 through the water produced branch pipe 11; the piston 24 in the gas-water separation device 2 is placed on the top, and The one-way valve 25 is in the open state, and the produced water flows into the outlet pipe 3, and enters the produced water pump through the control of the first stop valve 51 and the second stop valve 52; at the same time, the air blown by the air compressor passes through the fourth stop valve 54 , enter the aeration pipeline 6, and enter the membrane separation area through the aeration port 61 to flush and clean the membrane module 1. When the filter membrane of the membrane module 1 needs to be cleaned, the produced water pump is turned off, the second shut-off valve 52 is placed in a closed state, the fourth shut-off valve 54 is closed at the same time, and the third shut-off valve 53 is opened, so that the gas of the air compressor passes through the water outlet pipe 3 Enter the gas-water separation device 2, the one-way valve 25 in the gas-water separation device 2 is closed, the piston 24 moves down under the pressure, and the produced water is forced to flow out of the membrane module 1 in the radial direction and reverse direction of the filter membrane, and at the same time Contamination and blockage, play the role of backwash cleaning.

When the above-mentioned membrane bioreactor cleaning method is applied to a certain domestic sewage treatment, the aeration cycle is set to 540 seconds, and the dissolved oxygen concentration is 0.2-2 mg/L. The influent water quality of domestic sewage is: COD=300mg/L, BOD ₅ =120mg/L, TN=35mg/L, NH ₃ -N= 30mg/L. The water quality after treatment is: COD=38mg/L, BOD ₅ =18mg/L, TN=8mg/L, NH ₃ -N= 4mg/L, and the corresponding removal rates are 87.3%, 85.0%, 77.1% and 86.7%, the water quality of this product meets the national "Urban Sewage Treatment Plant Pollutant Discharge Standard" (GB18918-2002) Class A Standard.

Of course, the present invention is not limited to the above-mentioned embodiments. Those skilled in the art can also make equivalent modifications or replacements without violating the spirit of the present invention. These equivalent modifications or replacements are all included in the claims of this application. within a limited range.

Claims (10)

1. a membrane bioreactor, it is characterized in that: comprise membrane module and the gas and water separator that can be placed in muddy water mixed solution, described membrane module comprises filter membrane and by the film formed product water of described filter inner chamber, described product water inner chamber is communicated with described gas and water separator by water producing pipe, described gas and water separator comprises piston barrel and is located in described piston barrel and described piston barrel inner chamber is divided into the piston of ante-chamber and back cavity, described piston be provided with can conducting ante-chamber to the check valve of rear cavity direction, described water producing pipe is communicated with the ante-chamber of piston barrel, be communicated with the back cavity of described piston barrel and be provided with outer the practice midwifery outlet conduit of water pump and the steam line of external gas source.

2. membrane bioreactor according to claim 1, it is characterized in that: described membrane module is at least one, when membrane module is while being a plurality of, each membrane module is arranged in parallel, and described water producing pipe comprises the product water arm that is communicated with the product water inner chamber of each membrane module and will described in each, produce water arm and import the product water conduit tube of described gas and water separator.

3. membrane bioreactor according to claim 1 and 2, it is characterized in that: along described outlet conduit, be provided with the first stopping valve and the second stopping valve, described steam line imports described outlet conduit between described the first stopping valve and the second stopping valve, and described steam line is provided with the 3rd stopping valve.

4. membrane bioreactor according to claim 3, is characterized in that: also comprise aerating pipelines, described aerating pipelines forms some aeration opening below membrane module.

5. membrane bioreactor according to claim 4, is characterized in that: described aerating pipelines is communicated with described source of the gas and is in parallel with described steam line, and described aerating pipelines is provided with the 4th stopping valve.

6. membrane bioreactor according to claim 5, is characterized in that: described source of the gas is air compressor machine.

7. membrane bioreactor according to claim 6, is characterized in that: also comprise the Main Control Tank being communicated with described the first stopping valve, the second stopping valve, the 3rd stopping valve, the 4th stopping valve, product water pump and air compressor machine.

8. membrane bioreactor according to claim 1, is characterized in that: the water outlet of described product water pump is external to captation or advanced treatment apparatus.

9. membrane bioreactor according to claim 1, is characterized in that: described check valve is the one or more unilateral gates that can open to described back cavity that are located on described piston.

10. membrane bioreactor according to claim 1, is characterized in that: described filter membrane is ultra-filtration membrane.